Thallium-doped sodium iodide (NaI(Tl)) crystals are widely used in radiation detection applications, from gamma-ray spectroscopy to particle dark matter searches. However, if the crystal is exposed to relative humidity of even a few percent, its light emission degrades, making the crystal impractical as a detector. Surrounding the crystal with organic scintillators not only protects the surface of the crystal from humid air but also offers a new capability to tag backgrounds such as external gamma rays and surface contaminations. We developed a detector that is constructed by fully encasing a NaI(Tl) crystal in a plastic scintillator and then immersing the plastic-crystal assembly in liquid scintillator. Using data collected from this triple phoswich detector, a pulse shape analysis is able to identify the various radiation signals from the three scintillators. Additionally, we find that the crystal's emission quality is maintained for a month.
@article{arxiv.2205.08739,
title = {NaI(Tl) crystal scintillator encapsulated in two organic-scintillator layers with pulse shape data analysis},
author = {Jinyoung Kim and Yujin Lee and Byoung-cheol Koh and Chang Hyon Ha and Byung Ju Park and In Soo Lee and Hyun Su Lee},
journal= {arXiv preprint arXiv:2205.08739},
year = {2022}
}